This is a time-honored tradition. Do an IMDB search for the animated series "Gargoyles" and look at the number of ST:TNG actors that found other work as their TV series was winding down. Granted, the circumstances were a bit different, but the Alliance of Fox wasn't controlling access to the show, either.

Yeah my guy told me this a few months ago and I went straight to IMDB to see which episodes to really pay attention on. I think we are down to the last couple new ones ever now...or maybe they have shown already...I dunno. But recently (within the past 2 weeks) an episode called "Grudge Match" had Gina and Morena in it. It was nice to hear them. Amy Acker was also in it.

Morena is Black Canry BTW. Huntress is Amy.

Another one of the guys from Buffy/Angel was in it too. One of the watchers....his name escapes me now.
Also The Flash is played by the Lex Luthor from Smallville.

So yeah Fandom all around from the producers of JL

Honestly, the Whedonverse and the Justice League are just joined at the hip. I mean, Nathan has voiced Vigilante, Gina has Vixen, Morena has Black Canary (or is it Huntress), Adam has voiced characters...but so has Amy Acker and Juliet Landau (Huntress or Black Canary and Tala respectively). Who knows what other Joss-show actors have given into the childhood dream of being a superhero;)

BEB